The validator makes it clear what the issue is:
Code:
<div id="sections">
<ul>
<li>
<div class="slider-left-2">
<div class="slider-left">
<h1 id="slider1_header">Quality Web Design</h1>
<h2>Don't Just Design It - Grow It!</h2>
<img src="http://www.organicwebdesigns.co.uk/wp-content/themes/eBusiness/images/slider-line-Smooth-Blue.gif" alt="line" class="slider-line" />
<div style="clear: both;"></div>
MORE BUSINESS! MORE LEADS! MORE PROFIT! MORE SUCCESS!<br/> Quality Web Design & clever content is just the beginning.<br/> I'll set you up, get you noticed, maintain & update it.<br/> Then test & optimise your performance.
</div>
</div>
<div id="arrow-hd"><img src="http://organicwebdesigns.co.uk/wp-content/themes/eBusiness/images/arrow-hd.png" alt="arrow"/></div>
<a href="http://organicwebdesigns.co.uk/quote" class="cta">SOW YOUR SEED NOW!</a>
</div>
That </div> on line 132 is out of place, and is closing off the sections div prematurely.
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